If you guessed that quixotic has something to do with Don Quixote, you're absolutely right. The hero of the 17th-century Spanish novel El Ingenioso Hidalgo Don Quijote de la Mancha (by Miguel de Cervantes) didn't change the world by tilting at windmills, but he did leave a linguistic legacy in English. The adjective quixotic is based on his name and has been used to describe unrealistic idealists since at least the early 18th century. The novel has given English other words as well. Dulcinea, the name of Quixote's beloved, has come to mean mistress or sweetheart, and rosinante, which is sometimes used to refer to an old, broken-down horse, comes from the name of the hero's less-than-gallant steed.